Quarter	Millions of US Dollars
1980-07-01	25
1980-10-01	25
1981-01-01	25
1981-04-01	25
1981-07-01	25
1981-10-01	25
1982-01-01	65
1982-04-01	84
1982-07-01	81
1982-10-01	89
1983-01-01	88
1983-04-01	128
1983-07-01	150
1983-10-01	151
1984-01-01	154
1984-04-01	149
1984-07-01	147
1984-10-01	224
1985-01-01	344
1985-04-01	475
1985-07-01	838
1985-10-01	1098
1986-01-01	1545
1986-04-01	2083
1986-07-01	2521
1986-10-01	2624
1987-01-01	3014
1987-04-01	3198
1987-07-01	3431
1987-10-01	4335
1988-01-01	4500
1988-04-01	4402
1988-07-01	4602
1988-10-01	5053
1989-01-01	4830
1989-04-01	4703
1989-07-01	4822
1989-10-01	4871
1990-01-01	4596
1990-04-01	4702
1990-07-01	4991
1990-10-01	5075
1991-01-01	4895
1991-04-01	4926
1991-07-01	5244
1991-10-01	5530
1992-01-01	5116
1992-04-01	5391
1992-07-01	5843
1992-10-01	5794
1993-01-01	5858
1993-04-01	6596
1993-07-01	10188
1993-10-01	10545
1994-01-01	12403
1994-04-01	13052
1994-07-01	14319
1994-10-01	14904
1995-01-01	15759
1995-04-01	15740
1995-07-01	15316
1995-10-01	14819
1996-01-01	14398
1996-04-01	13975
1996-07-01	15424
1996-10-01	15895
1997-01-01	16251
1997-04-01	19255
1997-07-01	19337
1997-10-01	19173
1998-01-01	19434
1998-04-01	18802
1998-07-01	18018
1998-10-01	19264
1999-01-01	18571
1999-04-01	18746
1999-07-01	19068
1999-10-01	19532
2000-01-01	19145
2000-04-01	19122
2000-07-01	18681
2000-10-01	19482
2001-01-01	19006
2001-04-01	20964
2001-07-01	19805
2001-10-01	19748
2002-01-01	21238
2002-04-01	21272
2002-07-01	20645
2002-10-01	19771
2003-01-01	18926
2003-04-01	19272
2003-07-01	19876
2003-10-01	22713
2004-01-01	21748
2004-04-01	21428
2004-07-01	22867
2004-10-01	26629
2005-01-01	26942
2005-04-01	26619
2005-07-01	27863
2005-10-01	29079
2006-01-01	29109
2006-04-01	30020
2006-07-01	29848
2006-10-01	30849
2007-01-01	33165
2007-04-01	38640
2007-07-01	41587
2007-10-01	42434
2008-01-01	43428
2008-04-01	46237
2008-07-01	48372
2008-10-01	47796
2009-01-01	46496
2009-04-01	47268
2009-07-01	47483
2009-10-01	48923
2010-01-01	51766
2010-04-01	54939
2010-07-01	63305
2010-10-01	73934
2011-01-01	85772
2011-04-01	106626
2011-07-01	112607
2011-10-01	120181
2012-01-01	132315
2012-04-01	151675
2012-07-01	157422
2012-10-01	176456
2013-01-01	197394
2013-04-01	227422
2013-07-01	242238
2013-10-01	277612
2014-01-01	309152
2014-04-01	361486
2014-07-01	390013
2014-10-01	435212
2015-01-01	453388
2015-04-01	490169
2015-07-01	496958
2015-10-01	530461
2016-01-01	528956
2016-04-01	566959
2016-07-01	607173
2016-10-01	641223
2017-01-01	698111
2017-04-01	754992
2017-07-01	811367
2017-10-01	888323
2018-01-01	942882
2018-04-01	960592